JP2009163120A - Connection method for lens for imaging device, lens unit using connection method, and imaging device with built in lens unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens arrangement method facilitating correction when aligning optical axes of lenses of a lens unit constituted of the plurality of lenses, and preventing arrangement precision from depending strongly on an inner shape of a lens barrel. <P>SOLUTION: Provided is a method for connecting N (N is an integer of N≥2) lenses for an imaging device in series. Each lens is provided with a lens area in the central part and an outer peripheral rim area provided in an outer circumference of the lens area. An outer peripheral rim of one of the adjacent lenses is extended from an outer circumferential end part of the lens area toward the other lens side. The outer peripheral rim area is provided with a circular-arc tapered face inclined to the optical axis in the periphery of the leans area. The other one of the adjacent lenses is provided with a protrusion part with a rounded head top part along the outer circumference of the lens area, on a face of the outer peripheral rim facing the one lens. The protrusion part of the other lens is brought into contact with the circular-arc tapered face of the one lens in a point contact state, to be connected fixedly. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for connecting lenses for an imaging device, a lens unit using the connecting method, and an imaging device incorporating the lens unit. More specifically, in a lens unit composed of a plurality of lenses, it is easy to adjust the optical axis of each lens and to adjust and correct the distance between lenses, and the lens placement accuracy greatly depends on the shape of the lens barrel. The present invention relates to a lens arrangement method that does not, and is a method of connecting adjacent lenses.

  In recent years, it has become common for mobile tools such as mobile phones, PDAs, and notebook personal computers to be provided with simple imaging devices. This imaging apparatus is required to be capable of imaging with higher accuracy and higher image quality as well as downsizing. In order to satisfy these requirements, CCDs, C-MOSs, and the like as image sensors are increased in pixel count, and at the same time, in an optical lens system, two or more lenses are combined and arranged. Attempts have been made to improve image quality. As described above, when a plurality of lenses are combined and arranged, it is necessary to accurately correct the lens aberration by matching the optical axes of the arranged lenses with high accuracy. Therefore, a method for arranging a plurality of lenses in the lens barrel with high accuracy has been studied.

  Conventionally, as a method of disposing the plurality of lenses in the lens barrel, there is a method in which each lens is fixedly disposed by using the shape in the lens barrel formed on the inner peripheral wall surface of the inner peripheral surface of the lens barrel. An example of such a lens arrangement method is shown in FIG.

  FIG. 12 is a cross-sectional view of the lens unit 1 including three lenses in the optical axis direction. This lens unit includes a first convex lens 20, a first concave lens 21, a second convex lens 22, and a lens barrel 8. Then, as can be understood from FIG. 12, in order to fix and arrange each of the above-mentioned three lenses at predetermined positions on the inner peripheral surface of the lens barrel 8, a predetermined value is provided on the inner peripheral surface of the lens barrel 8. A first step 26, a second step 27, and a third step 28 formed with a diameter difference are provided. Then, the lenses 20, 21, and 22 molded in accordance with the diameters of the respective steps are sequentially inserted into the lens barrel. The lenses 20, 21, 22 inserted in this way are placed in contact with the steps 26, 27, 28. In this way, each lens is fixedly arranged in the lens barrel.

  Further, Patent Document 1 discloses a lens unit in which a plurality of lenses having thick protrusions in the optical axis direction are arranged in the optical axis direction on the outer peripheral portion that does not affect the imaging function. The side surfaces of the projecting edges are joined directly or indirectly via an intervening member to maintain a predetermined air gap, and the lenses are fixed to each other while maintaining their relative positions. A lens unit characterized by this is disclosed. That is, the present invention discloses a method of connecting lenses without using a lens frame by joining the protruding edges formed on the outer peripheral portion of each lens, and bonding and fixing them. .

  Patent Document 2 states that “a lens unit composed of a plurality of injection-molded plastic lenses, whose inner diameter is formed with a lens core processing reference diameter by the processing reference surface in the first lens core mold. A convex portion whose outer diameter is formed substantially the same as the lens core processing reference diameter by a first lens having a concave portion and a second lens mold having a processing reference diameter substantially the same as the lens core processing reference diameter. And connecting the first lens and the second lens in a different manner by fitting the convex portion of the second lens and the concave portion of the first lens. A "characteristic lens unit" is disclosed. That is, according to the present invention, in order to fix and arrange the first lens and the second lens, the concave portion formed in the inner peripheral portion of the lens core of the first lens and the outer peripheral portion of the lens core of the second lens are formed. In this method, the lenses are fixedly connected to each other by fitting the convex portions.

  Patent Document 3 discloses "a plastic lens having a pressing surface in the optical axis direction formed in a conical shape at the center of the optical axis". That is, according to the present invention, a conical tapered surface centered on the optical axis is provided on the outer periphery of the lens, and the tapered surfaces provided in adjacent lenses are brought into contact with each other and pressed to fix the lens. The method of connecting and arranging each other is adopted.

  Further, Patent Document 4 includes a lens barrel and two or more lenses inserted and arranged in the lens barrel. The first lens is centered on the optical axis at the inner wall portion of the rib on the outer periphery of the edge. The second lens has a conical surface centered on the optical axis on the outer wall of the rib on the outer periphery of the edge and abutting on the conical surface formed on the inner wall of the rib of the first lens. Further, the first lens has a surface perpendicular to the optical axis, and the lens barrel has a vertical receiving surface abutting on the surface perpendicular to the first lens. By inserting the lens in the lens barrel, the vertical surface of the first lens is brought into contact with the vertical receiving surface of the lens barrel, and the conical surface of the rib inner wall portion of the first lens And the conical surface of the rib outer wall portion of the second lens are in surface contact with each other and housed in the lens barrel, and the conical slope of the rib outer wall portion of the second lens The second lens is fixed to the lens barrel so as to sandwich the outer periphery of the first lens by the vertical receiving surface of the lens barrel, and the first lens is contacted by the surface of the conical surface. The lens and the second lens are provided with a clearance between opposing surfaces other than the conical surface, and the first lens and the second lens are simultaneously positioned in the optical axis and the optical axis direction. A device is disclosed. That is, according to the present invention, the tapered surfaces provided on each of the lenses to be connected are brought into contact with each other to connect the lenses, and a part of the outer peripheral portion of each lens is in contact with the inner wall surface of the lens barrel. A method of positioning the lenses and fixing the lenses is adopted.

Japanese Patent Laid-Open No. 62-153908 JP 2004-205574 A JP-A-56-149010 Japanese Patent No. 3739295

  However, as shown in FIG. 12, when the method of arranging each lens by each step provided on the inner peripheral surface of the lens barrel is adopted, the lens outer periphery of each of the arranged lenses has an inner lens barrel inner periphery. Since it is fixed in contact with the surface, the lens placement accuracy such as optical axis alignment between the lenses and the distance between the lenses depends on the formation accuracy of the inner peripheral wall surface provided on the inner peripheral surface of the lens barrel. become. In this case, in order to accurately create the inner wall surface shape of the lens barrel, it is necessary to improve the manufacturing accuracy of the mold when manufacturing the lens barrel member, and the production cost is significantly increased. Considering the alignment of the optical axes of the lenses, it is difficult to finely adjust the lens position after the lens is arranged in the lens barrel, and it is difficult to align the optical axes.

  And in the case of the lens arrangement method disclosed in Patent Document 1, the lenses are connected to each other by joining the projecting edges provided on the outer peripheral portions of adjacent lenses. It is not affected by the shape of the inner peripheral surface of the lens barrel. However, the optical axis adjustment of the lenses to be connected must be performed simultaneously with the joining of the projecting edges of each lens. Therefore, the smaller the lens, the more difficult it is to work. Further, as the number of lenses to be connected increases, it is not preferable because sufficient optical axis adjustment is performed and it becomes difficult to accurately connect the lenses. Furthermore, as shown in FIG. 5 of Patent Document 1, it is said that the taper surfaces are in contact with each other, thereby satisfying the required quality of both elements of the lens interval and the optical axis shift. Although it is determined by the error of the taper angle, it is difficult to accurately form the taper angle of the taper surface. Therefore, as a result, it becomes difficult to bring the tapered surfaces into precise surface contact.

  In addition, the lens arrangement method disclosed in Patent Document 2 is a method of connecting adjacent lenses by diameter fitting between lenses. This lens-to-lens connection method allows the concave portion of the first lens and the convex portion of the second lens to be fitted to each other without generating a gap. However, in the method disclosed in Patent Document 2, even if the concave portion of the first lens and the convex portion of the second lens are diameter-fitted, they cannot be arranged without a gap. Arise. Therefore, the optical axis shift between the lenses inevitably occurs, and the directionality of the shift is not constant, so that the quality of the lens unit is likely to vary. Furthermore, when trying to mass-produce lenses for obtaining the optimal fitting state used in the method disclosed in Patent Document 2, a plurality of lens production molds are inevitably required, and the optical axis accuracy and lens interval accuracy are improved. In order to optimize, it is essential to correct the mold. From the viewpoint of manufacturing technology, complicated work is required, which increases the management cost when manufacturing the lens, which is not preferable. Furthermore, it is difficult to change the fitting state once fitted, and it becomes difficult to reassemble and finely adjust the optical axis. In particular, when the lens is small, it is difficult to correct the lens, which is not preferable because it imposes a heavy burden on the operator.

  Furthermore, in the lens arrangement method disclosed in Patent Document 3, a pressing surface in the optical axis direction formed conically around the optical axis is provided on the outer periphery of each lens, and the pressing surfaces of adjacent lenses are mutually connected. This is a method of abutting and connecting lenses. However, although a method of connecting the lenses by applying a pressing force in the optical axis direction to the conical contact surfaces is employed, it is difficult to bring the conical contact surfaces into contact with each other with high accuracy. In addition, the method of connecting the lenses by applying a pressing force in the optical axis direction to the conical contact surface has a wide pressing surface, so that when the optical axis is adjusted, the pressing surfaces are fixed to each other, and the optical axis is fixed. There is a problem that it is difficult to make fine adjustments. In addition, there is a problem that the operator cannot accurately grasp the contact positions in the pressing surfaces of both of the lenses to be connected. Also, with respect to Patent Document 4, the method of connecting lenses by applying a pressing force in the direction of the optical axis to the contact surface is the same as in Patent Document 3, because the pressing surface is wide. In addition, the pressing surfaces are fixed to each other, and there is a problem that fine adjustment of the optical axis is difficult.

  Accordingly, as a result of intensive studies, the present inventors have adopted the following lens coupling method for an image pickup device in order to solve the above-described problems, and have solved the above-described problems. The outline of the present invention will be described below.

Imaging Device Lens Connection Method According to the Present Invention: The imaging device lens connection method according to the present invention is a method of serially connecting N lenses (an integer of N ≧ 2) for an imaging device. (A) Each of the N lenses includes a central lens region and an outer peripheral rim region provided on the outer periphery of the lens region, and (B) one lens connected adjacently has an outer periphery thereof. The rim region extends from the outer peripheral edge of the lens region to the other lens side with a predetermined thickness, and the outer rim region has an arcuate tapered surface inclined with respect to the optical axis around the lens region. (C) The other lens connected adjacently includes a raised protrusion shape portion obtained by rounding the top of the head on the surface of the outer peripheral rim region facing the one lens along the outer periphery of the lens region. ) The raised protrusion shape of the other lens The lens position is adjusted by making contact with the arcuate taper surface of the outer peripheral rim region of the one lens while making point contact, and the arcuate taper surface of one lens and the raised protrusion shape of the other lens are in point contact. In this state, it is fixedly connected.

  And among the connection methods of the lens for imaging devices which concerns on this invention, it is preferable to employ | adopt the following specific methods. A method of serially connecting N lenses (an integer of N ≧ 2) for an imaging apparatus, wherein (i) each of the N lenses has a lens area at the center and an outer periphery of the lens area (Ii) the (n−1) th lens (hereinafter simply referred to as the “n−1th lens”) of N lenses (2 ≦ n (integer) ≦ N). The outer peripheral rim region extends with a predetermined thickness from the outer peripheral edge of the lens region toward the nth lens (hereinafter simply referred to as “nth lens”), and the lens in the outer peripheral rim region. The inner peripheral surface following the region includes bank-shaped arc-shaped tapered surfaces inclined from the nth lens side toward the lens region of the (n−1) th lens, and (iii) N (2 ≦ n (integer) ≦ N The n-th lens of the lens (1) has a crown on the surface of the outer peripheral rim region facing the n-1 lens. (Iv) the raised protrusion shape of the nth lens, and the arcuate taper of the outer peripheral rim region of the n-1 lens. The lens position is adjusted by making contact with the surface in a point contact state, and the arcuate tapered surface of the (n-1) th lens and the raised protrusion shape of the nth lens are fixedly connected in a state of point contact. To do.

  And in the connection method of the lens for imaging devices which concerns on this invention, the circular arc-shaped taper surface provided in the outer periphery rim area | region of the said (n-1) th lens is the range whose cross-sectional inclination | tilt angle is 30 degrees-60 degrees with respect to an optical axis. It is preferable to do.

  On the other hand, in the method for connecting a lens for an imaging device according to the present invention, the raised protrusion shape portion provided in the outer peripheral rim region of the nth lens is provided along the outer periphery of the lens region of the nth lens, and the raised protrusion The cross-sectional shape in the width direction of the shape part is preferably a substantially semicircular shape or a dome shape.

  Furthermore, it is preferable that the raised protrusion shape portion provided in the outer rim region of the nth lens is provided as a continuous or discontinuous shape along the outer periphery of the lens region of the nth lens.

  In the imaging device lens coupling method according to the present invention, it is preferable that resin lenses are used for all of the N lenses (an integer of N ≧ 2) for the imaging device.

  In the imaging device lens coupling method according to the present invention, it is also preferable to use a combination of a resin lens and a glass lens for the N (N ≧ 2) imaging device lenses.

Lens unit according to the present invention: The lens unit according to the present invention is configured by connecting N (an integer of N ≧ 2) lenses in series using any of the imaging device lens coupling methods described above. It is characterized by being obtained.

Imaging device according to the present invention: The imaging device according to the present invention is characterized in that a lens unit in which the above-mentioned N (N ≧ 2) integer lenses are connected in series is incorporated in a lens barrel. is there.

   By adopting the imaging device lens coupling method according to the present invention, when coupling a plurality of lenses, the contact position between the lenses is clearly defined without strongly depending on the shape of the inner wall surface in the lens barrel that houses the lenses. Therefore, it is possible to minimize the error in the lens-to-lens distance and eliminate the need for optical axis alignment between the lenses. Moreover, even after the lenses are once positioned, it is possible to adjust the optical axis and the distance between the lenses that are easily and accurately connected by separating the positioned lenses. Therefore, when the lenses are positioned, it is possible to repeatedly adjust the coupling position of the lenses so that the optical performance of each lens can be sufficiently extracted. Therefore, the lens unit obtained by connecting the lenses using the imaging device lens connecting method according to the present invention is excellent in the optical axis accuracy of the plurality of lenses and the accuracy of the distance between the lenses. As a result, good optical characteristics are provided. Further, when the lens unit is accommodated in the lens barrel, it is only necessary to form an engagement state between at least one lens constituting the lens unit and the shape formed on the inner peripheral wall surface of the lens barrel. It is possible to arrange a plurality of lenses connected to each other, and assembling as an imaging device is easy and low cost.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for connecting lenses for an imaging device according to the present invention will be described below with reference to the drawings.

Form of Method for Connecting Lenses for Imaging Device According to Present Invention: In the method for connecting lenses for imaging device according to the present invention, N lenses (an integer of N ≧ 2) for the imaging device are connected in series. It is. Each of the N lenses used here includes a central lens region and an outer peripheral rim region provided on the outer periphery of the lens region. In the present invention, the outer peripheral rim region of the lens means all the regions existing on the outer periphery of the lens region functioning as a lens.

  FIG. 1 typically shows an image of connecting two lenses as a cross-sectional view in order to facilitate understanding of this connecting method. FIG. 1A shows one lens A to be connected, and the outer peripheral rim region has a different form in which an arcuate tapered surface 4 inclined with respect to the optical axis L is provided around the lens region. Is illustrated. FIG. 1B shows the other lens B, the top of the outer peripheral rim region facing at least one lens A, corresponding to the arcuate tapered surface 4 of each lens A. The form which equips the outer periphery of a lens area | region with the protruding protrusion shape part 5 which round-processed this is illustrated.

  FIG. 2 illustrates four variations in which three lenses are connected using the method for connecting lenses for an imaging device according to the present invention. Here, an example of a variation of the combination of one lens (lens A or lens B) and the other lens (lens B for lens A, lens C for lens B) is described. As can be understood from FIG. 2, at least one outer peripheral rim region of one lens connected adjacently extends with a predetermined thickness from the outer peripheral edge of the lens region toward the other lens side. The outer peripheral rim region has an arcuate tapered surface inclined with respect to the optical axis around the lens region.

  At this time, the other lens connected adjacently to one lens has at least one raised protrusion shape part obtained by rounding the crown on the surface of the outer peripheral rim region facing the one lens on the outer periphery of the lens region. Prepare along.

  Using the lens as described above, the raised protrusion shape of the other lens is brought into contact with the arc-shaped tapered surface of the outer peripheral rim region of the one lens to adjust the lens position. The arcuate tapered surface of one lens and the raised protrusion shape of the other lens are fixedly connected in a point contact state.

Hereinafter, in the method for connecting lenses for an imaging apparatus according to the present invention, a description will be given using a typical lens arrangement pattern among the methods for connecting N lenses for an imaging apparatus in series. Here, what is referred to as N means an integer of N ≧ 2. FIG. 3 schematically shows an image obtained by connecting _N lenses (R _{1 to} R _N ) as a longitudinal section. Note that although an image in which _{1 to N} lenses (R _{1 to} R _N ) are arranged is used in order to specify the present invention, the lens R ₁ is not necessarily included in the imaging device. It is intended to mean a top lens which is of the object side rather, in some cases the lens R _N is first lens on the object side. However, in the following description, based on the assumption that arranging the first lens R ₁ closest to the object side will be mainly described.

  Then, there is no special upper limit for the N lenses, and any of the N lenses may be a convex lens, a concave lens, a polarizing lens, a protective lens, or the like. However, in order to employ the method for connecting lenses for an imaging device according to the present invention, it is necessary to have a lens region at the center of the lens and an outer rim region at the outer periphery of the lens region.

  Here, the concept for connecting the “n−1th lens” and the “nth lens” when connecting N lenses will be described. Here, n satisfies the relationship of 2 ≦ n (integer) ≦ N, and the image is a lens at a position as shown in FIG. That is, the “n−1th lens” and the “nth lens” are connected by the “outer rim region of the n−1th lens” and the “outer rim region of the nth lens”. Therefore, it is appropriate to extract and describe the “n-1 lens” and the “nth lens” in FIG. 3, but for the sake of explanation, the description will be made using the first lens and the second lens. . FIG. 4 shows a schematic cross-sectional view of the n-1 lens (= first lens) as FIG. 4A and a perspective view as FIG. 4B for reference.

Here, the (n−1) -th lens R _n-1 having the schematic cross section shown in FIG. 4 has a lens region 2 _{n-1 at} the center of the lens, and is located at the outer periphery of the lens region 2 _n-1. And an outer peripheral rim region 3 _n−1 . And the outer periphery rim area | region 3 _n-1 is extended with predetermined thickness toward the nth lens side from the outer _- periphery edge part of lens area | region 2 _n-1 . Here, the “predetermined thickness” will be described. “Predetermined thickness” means “optical axis direction rim thickness T _L ” along the optical axis direction L of the lens and “lens radial direction rim thickness T _D ” perpendicular to the optical axis direction L of the lens. It is used as a term that encompasses both concepts. The “rim thickness in the optical axis direction T _L ” and the “rim thickness in the lens radial direction T _D ”, which are the thicknesses of the outer peripheral rim region, are within the “arc-shaped taper surface” and the “protrusion protrusion shape portion”. As long as the thickness can provide at least one shape, no particular limitation is required.

Further, as can be understood from FIG. 4A, the n-1th lens has an inner peripheral surface following the lens region of the outer peripheral rim region _3n-1 , from the nth lens side to the lens of the n-1th lens. It is necessary to provide a bank-shaped arcuate taper surface 4 _n-1 inclined toward the region. Then, the arc-shaped tapered face 4 _n-1 functions as a coupling surface of the raised projection-shaped portion 5 _n of the n lens R _n to be described later.

In this case, the arcuate tapered surface 4 _n-1 preferably has a cross-sectional inclination angle θ with respect to the optical axis in a range of 30 ° to 60 °, as shown in FIG. And it is most preferable that the cross _- sectional inclination angle of the arc-shaped tapered surface 4 _n-1 is 45 °. Arcuate tapered surface external force applied perpendicular to the (pressure raised projected part 5 _n of the n lens R _n to be described later is added to the arc-shaped tapered surface), one of the orthogonal directions of the optical axis direction or optical axis This is because it can be distributed almost evenly. However, it is difficult to form the arcuate tapered surface 4 _n-1 having a complete cross-sectional inclination angle of 45 °. Therefore, if the cross-sectional inclination angle is in the range of 30 ° to 60 °, the external force applied perpendicularly to the arcuate taper surface is extremely high in either the optical axis direction or the direction orthogonal to the optical axis. The optical axis can be adjusted at the same level as the arcuate tapered surface 4 _n-1 when the cross-sectional inclination angle is 45 °. Therefore, if the cross-sectional inclination angle is out of the range of 30 ° to 60 °, it is difficult to perform high-precision optical axis adjustment between the nth lens Rn and the n−1th lens. In addition, if the cross-sectional inclination | tilt angle of this arc-shaped taper surface 4 is the range of 30 degrees-60 degrees, according to the material of a lens, the shape of lens area | region 2 _n-1 , a lens size, etc., the arc-shaped taper surface 4 _{The n-1} cross _- sectional inclination angle can be arbitrarily selected.

Next, as can be understood from FIG. 5, the n-th lens R _n is a raised protrusion-shaped part obtained by rounding the top of the head on the surface of the outer peripheral rim region 3 _n facing the n−1th lens R _n−1 side. 5 _n is provided along the outer periphery of the lens region 2 _n of the nth lens. FIG. 5 shows a schematic cross-sectional view of the nth lens (= second lens) as FIG. 5A and a perspective view as FIG. 5B for reference.

Then, the raised projection-shaped portion 5 _n that the outer peripheral rim region 3 provided on _n of the n lens R _n are those provided along the outer periphery of the lens region of the n lens, the width direction of the raised projection-shaped portion 5 _n It is desirable that the cross-sectional shape in FIG. 6 is a substantially semicircular shape or a dome shape as shown in any of FIGS. By providing such a cross-sectional shape, a good point contact state with the arc-shaped tapered surface 4 _n-1 of the _n- 1th lens is formed, and the arrangement state at a level where the optical axis adjustment of both lenses is unnecessary. Is obtained. Here, the height 6 of the raised protrusion-shaped portion is important as an element for adjusting the inter-lens distance between the ( _{n−1) th} lens R _n−1 and the n th lens R _n. It depends on the required standard. Accordingly, it is considered that there is no need to provide a particular limitation on the concept of the height of the protrusion-shaped portion. Note that "adjustment of the lens position" in the present invention, the n-1 lens R _n-1 and by superposing the n-th lens R _n, as viewed in cross section, a tapered surface and the raised projection-shaped portion in As the state of point contact, sufficient optical axis alignment and accurate inter-lens distance adjustment are performed to accurately position the lens.

Then, the raised projection-shaped portion 5 _n provided on the outer peripheral rim region 3 _n of the n-th lens R _n is formed at a portion indicated by the broken line in the front view of the n-th lens R _n in FIG. That is, as shown in FIG. 7 (a), it shows a raised projection-shaped portion 5 _n provided in a state of continuous along the periphery of the lens region 2 _n of the n-th lens R _n. Then, as shown in FIG. 7 (b), it shows a state which is provided discontinuously along the periphery of the lens region 2 _n of the n-th lens R _n. In such a case, the short sub-protrusion protrusion shapes 5 _{n (1) to} 5 _{n (3)} constitute the protrusion protrusion shape portion 5 _n along the outer periphery of the lens region 2 _n of the n-th lens R _n as a whole. . Sub raised protrusion shape at this time, be provided with three or more number, preferably the n-1 lens R _n-1 and the positioning accuracy when performing the connection between the n-th lens R _n easily obtained. Furthermore, there is no particular limitation regarding the length of the sub-projection protrusion shape.

The connection of the first n-1 lens _{R n-1} and the n lens _{R n} which have been described above, as shown in FIG. 8 (a), a raised protrusion shape _{5 n} of the n-th lens _{R n,} the to the n-1 lens the arcuate tapered surface 4 _n-1 of the outer peripheral rim region 3 _n-1 of the R _n-1, by contact in a state of point contact at a contact point 7 performs positioning of the lens, It maintains its state, the like for fixing with adhesive and the n lens R _n and the (n-1) lens R _n-1. As a result, as shown in FIG. 8B, the arcuate tapered surface of the (n-1) th lens and the raised protrusion shape of the nth lens are fixedly connected in a point contact state. Incidentally, since the n-1 lens R _n-1 and the n-th lens R _n is a state of point contact, but before performing the fixed connection with an adhesive or the like, in order to perform optical axis alignment again It is possible to easily adjust the lens position by separating the lenses.

Then, in the n-1 lens _{R n-1} of the arc-shaped tapered face _{4 n-1} is the contact point 7, in the raised projection-shaped _{5 n} of the n lens _{R n,} a state of point contact when viewed in cross-section. The n-1 lens R _n-1 of the arc-shaped tapered face 4 _n-1 and the raised projection-shaped 5 _n and contacts of the n lens R _n, maintaining the inter-good light axis adjustment and proper lens distance These lenses are connected together. The connection of this time, or using an adhesive, a variety of methods, such as fusing by heating the outer peripheral rim portion of the n-1 lens R _n-1 and an outer peripheral rim portion of the n-th lens R _n Any method may be used as long as it can be adopted and the lenses can be fixed to each other. As described above, the lens unit 1 can be assembled by connecting N lenses. In addition, the lens unit in which N lenses are connected by the lens connecting method described above can be connected to each other while maintaining a stable optical axis, and can exhibit good optical performance.

The following is clearly stated as a precaution. Assuming arranged first lens R ₁ closest to the object side, at least, an arcuate tapered surface 4 _n-1 of the outer peripheral rim region 3 _n-1 of the (n-1) th lens R _n-1 in the above description similar arcuate tapered surface, it is necessary to provide the circumferential rim region 3 ₁ facing the second lens R _2. The lens R _N to place closest to the imaging side, at least, the raised projection provided on the n lens R _n circumferential rim region 3 _n (n-1) th lens R _n-1-side surface of the above description It needs to have a similar ridge projecting shapes 5 _n and shape 5 _n. Among the N lenses, an intermediate lens (2 ≦ n (integer) ≦ N−1) is an arc-shaped taper of the outer peripheral rim region 3 _n−1 of the above-described n−1th lens R _n−1. surface 4 and _n-1 the same arcuate tapered surface, similar to the raised and the n lens R _n raised protrusion shape 5 _n provided on the outer peripheral rim region 3 _n (n-1) th lens R _n-1-side surface of the Combined with the protrusion shape. Although previously stated just in case, also when placing the closest n-th lens R _n on the object side it can be applied the same concept as described above.

Such a n-1 lens R _n-1 and the n-th lens R _n, the optical characteristics of the lenses, good impact properties, in consideration of the temperature characteristics and the like, should be selected material. It is preferable to employ a resin-based lens using an acrylic resin, a polycarbonate resin, or the like as a plastic resin having characteristics that match the required characteristics of the imaging device lens. This resin-based lens is characterized by being lightweight and inexpensive. In addition, the resin-based lens is easy to mold and use as a lens, and can be mass-produced and is excellent in production cost. Therefore, in the method for connecting lenses for an imaging device according to the present invention, it is preferable to assemble the lens unit 1 using resin lenses for all of the N lenses.

  However, it is said that the resin-based lens is more likely to change the refractive index of the lens depending on the environment because the lens volume changes more easily due to changes in temperature and humidity than the glass-based lens. When the volume of the lens changes in this way, the focal length changes, which may reduce the quality of an image to be captured. In contrast, glass lenses are less susceptible to lens volume changes due to temperature, humidity, etc. as described above than plastic lenses. Therefore, compared to the case where the lens unit 1 using only a resin lens is used, in order to perform higher-quality imaging, the lens volume is less likely to be affected by the temperature and humidity of the use environment than the plastic lens. It is also preferable to use a so-called glass-based lens. Therefore, ideally, it is most preferable to use only the glass-based lens in the method for connecting the lenses for the imaging device according to the present invention.

Then, the lens unit 1 is configured by combining the resin-based lens and the glass-based lens, and it is also possible to suppress the variation in optical characteristics as much as possible according to the use environment. For example, the resin lens used in the n-1 lens _{R n-1,} using a glass-based lens to the n lens _{R n.} Or, using a glass-based lens to the n-1 lens R _n-1, it is such a resin system lens to the n lens R _n. Furthermore, using a glass-based lens only in the first lens R _1, when using other lenses R ₂ to R _n in the resin system lens, the lens unit 1 by, for example arranging the resin lens and a glass-based lens alternately It is also possible to assemble.

The lens unit 1 described above enables only the N lenses for the imaging apparatus to be aligned with each other by enabling good optical axis alignment during the lens connecting operation. Is. In the lens unit 1, as shown in FIG. 9, only the first lens R ₁ is in contact with the shape of the inner wall surface 9 of the lens barrel 8, and the other lenses are in contact with the inner wall surface 9 of the lens barrel 8. Will not do. Therefore, even finish precision of the inner wall surface 9 of the lens barrel 8, only now it is sufficient to consider the relationship between the first lens R _1, there is no need to consider the overall finish precision of the inner wall surface 9 of the lens barrel 8 .

Then, a cross-sectional view and a perspective view of a state in which the lens unit 1 in which the first lens R ₁ and the second lens R ₂ are connected to each other are built in the lens barrel 8 by using the imaging device lens connecting method according to the present invention. This is illustrated in FIG. The lens unit 1 accommodated in the lens barrel 8 shown in FIG. 10 is suitable for the imaging device 30 of the mobile phone 40 with an imaging function shown in FIG. The lens unit 1 mounted on the mobile phone 40 with the imaging function is characterized in that it uses the above-described lens connecting method for an imaging device.

  The imaging apparatus lens coupling method according to the present invention can easily adjust the optical axes of a plurality of lenses to be coupled, with a simple configuration. Moreover, it is easy to secure a stable inter-lens distance among the N lenses, and good optical performance as a lens unit can be maintained. Therefore, if the lens unit manufactured using the imaging device lens coupling method according to the present invention is used, the optical characteristics of the imaging device can be easily improved without using a complicated structure and method. Therefore, the lens unit according to the present invention can further enhance the effect of the image quality improvement means such as improving the number of pixels as the imaging device and improving the performance of the small imaging device itself, compared with the conventional one. This makes it possible to provide a high-quality imaging device.

It is the schematic cross section which showed the typical example in the case of connecting two lenses using the connection method concerning this invention. It is the schematic cross section which showed the typical example in the case of connecting three lenses using the connection method concerning this invention. It is the longitudinal cross-sectional view which showed typically the image which connected N lenses (R1-RN). It is a schematic diagram of the longitudinal cross-section of an n-1 lens. It is a schematic diagram of the longitudinal cross-section of an nth lens. It is a cross-sectional schematic diagram in the width direction of the protruding protrusion shape part provided in the outer periphery rim region of the nth lens. It is a front view of the nth lens for understanding the protruding projection shape portion provided in the outer peripheral rim region of the nth lens. It is a longitudinal cross-sectional view for demonstrating the connection state of an n-1 lens and an nth lens. It is a longitudinal cross-sectional view for demonstrating the accommodation state in the lens-barrel of the lens unit which concerns on this invention. It is sectional drawing and perspective view which show typically the state which incorporated the lens unit which connected the 1st lens and the 2nd lens in the lens-barrel using the connection method of the lens which concerns on this invention. It is drawing which illustrated the imaging device incorporating the lens unit shown in FIG. It is a schematic diagram for demonstrating the conventional method of arrange | positioning each lens by each level | step difference provided in the internal peripheral surface of the lens-barrel.

Explanation of symbols

R ₁ to R _N first lens to N-th lens first lens unit _{2, 2} 1 to 2 _N lens regions _3,3 1 to 3 _N outer peripheral rim region _{4, 4} 1 to 4 _N arcuate tapered surfaces ₅ 1 5 _N raised projection shape portion 6 height (of the raised projection shape portion) 7 contact point 8 lens barrel 9 inner wall surface 20 first convex lens 21 first concave lens 22 second convex lens 26 first step 27 second step 28 third step 30 with the imaging apparatus 40 imaging function mobile phone T _L optical axis direction rim thickness T _D lens radial rim thickness

Claims (9)

A method of serially connecting N lenses (an integer of N ≧ 2) for an imaging device,
Each of the N lenses includes a central lens region and an outer peripheral rim region provided on the outer periphery of the lens region,
One lens connected adjacently has an outer peripheral rim region extending from the outer peripheral edge of the lens region toward the other lens with a predetermined thickness, and the outer peripheral rim region is light-transmitted around the lens region. An arcuate tapered surface inclined with respect to the axis;
The other lens that is connected adjacently has a raised protrusion-shaped part obtained by rounding the crown on the surface of the outer peripheral rim region facing the one lens along the outer periphery of the lens region.
The raised projection shape of the other lens is brought into contact with the arcuate taper surface of the outer peripheral rim region of the one lens in a point contact state to adjust the lens position, and the arcuate taper surface of one lens and the other are adjusted. A method of connecting lenses for an imaging device, wherein the lens is fixedly connected in a state of point contact with the raised protrusion shape of the lens. A method of serially connecting N lenses (an integer of N ≧ 2) for an imaging device,
Each of the N lenses includes a central lens region and an outer peripheral rim region provided on the outer periphery of the lens region,
Of the N lenses (2 ≦ n (integer) ≦ N), the n−1th lens (hereinafter simply referred to as “the n−1th lens”) has an outer peripheral rim region that is an outer peripheral edge of the lens region. An inner peripheral surface that extends from the end toward the nth lens (hereinafter simply referred to as “nth lens”) with a predetermined thickness and that follows the lens region of the outer peripheral rim region is an nth lens. A bank-like arcuate taper surface inclined from the side toward the lens region of the (n-1) th lens;
Of the N lenses (2 ≦ n (integer) ≦ N), the nth lens has a raised protrusion shape portion obtained by rounding the crown on the surface of the outer peripheral rim region facing the n−1th lens. Along the outer periphery of the lens area of the n lens,
The raised projection shape of the n-th lens is brought into contact with the arc-shaped tapered surface of the outer peripheral rim region of the n-1 lens in a point-contacted state to adjust the lens position, and the arc shape of the n-1 lens is adjusted. The method of connecting a lens for an imaging apparatus according to claim 1, wherein the taper surface and the raised protrusion shape of the nth lens are fixedly connected in a point contact state. The imaging device lens according to claim 2, wherein the arcuate tapered surface provided in the outer peripheral rim region of the n−1th lens has a cross-sectional inclination angle in a range of 30 ° to 60 ° with respect to the optical axis. Consolidation method. The raised protrusion shape portion provided in the outer rim region of the nth lens is provided along the outer periphery of the lens region of the nth lens,
The method of connecting lenses for an imaging device according to claim 2 or 3, wherein a cross-sectional shape of the raised protrusion-shaped portion in the width direction is a substantially semicircular shape or a dome shape. 5. The raised protrusion-shaped portion provided in the outer peripheral rim region of the nth lens is provided as a continuous or discontinuous shape along the outer periphery of the lens region of the nth lens. The connection method of the lens for imaging devices of description. 6. The method of connecting lenses for an imaging device according to claim 1, wherein resin lenses are used as all the N lenses (an integer of N ≧ 2) for the imaging device. The imaging device lens coupling method according to claim 1, wherein the N imaging device lenses (N ≧ 2) are a combination of a resin lens and a glass lens. A lens unit obtained by serially connecting N (an integer of N ≧ 2) lenses using the imaging apparatus lens coupling method according to claim 1. . 9. An imaging apparatus comprising: a lens unit in which N lenses (integers of N ≧ 2) according to claim 7 or 8 are connected in series and are built in a lens barrel.

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